I went to visit my girlfriend at work one night. She works as a nurse and was working the night shift so I was trying to be a good guy and stop by at around 2 am to bring her a cup of coffee and some snacks. The receptionist at the front desk tried to page my girlfriend but she did not answer so she let me back into the unit since I have been there many times before.

It was really quiet and I did not see anyone at the nurse's station or in the break room so I just left a note and the coffee in the break room for my girlfriend. As I was walking out I heard a low muffled moaning sound coming from a dark patient room. The door was slightly ajar and when I looked in, my girlfriend was straddling a young medical resident sitting in one of the visitor's chairs and her ass was bouncing up and down on his dick. His pants were down around his ankles and her scrub pants were on the patient bed. They both had their tops on I guess in case they needed to get dressed quick but seeing as they didn't even shut the door I don't think they were too concerned. It did not look like anyone else was working that night either.

I came in at the end of their fucking as I was only watching for a few minutes before he ejaculated inside her. I was really jealous and super hard at the same time watching her beautiful ass and pussy work his dick so when she got home early that morning I fucked her harder than usual and had a really strong orgasm. I am not going to tell her what I saw and maybe try to catch her doing it again.